Justification. It's one of those "Christianese" words that Christians use all the time without really understanding its true definition. Many half-sorta-kinda-true definitions exist out there, but what about the biblical definition?
The Bible is replete with phrases that refer to Christians being "justified by faith" or "justified by His grace." But, really, what does that mean?
Justification is a legal act of God in which He declares Christ's righteousness to cover our sin and forgives us our trespasses. We're justified before God because of Christ. Wayne Grudem adds to this in "Christian Beliefs: Twenty Basics Every Christian Should Know:"
The sins of those justified are considered forgiven because God considers their sins as belonging to Christ, and Christ already paid the penalty for those sins. But not only does God consider those sins as belonging to Christ, he also considers Christ's righteousness as belonging to us. Christ took the place of guilt that we all deserved so that we could take the place of acceptance we all long for."That is justification.
But a common, catchy definition that's been taught widely (this was the definition that first introduced me to the doctrine of justification) is "just as if I didn't sin." Unfortunately, there's a problem with that definition. It puts more emphasis on us than Christ. My dad likes to say, "just as if Christ didn't sin, because He didn't." My youth leader refers to justification as Christ "imputing his righteousness on us." It was Christ who justified us by his death. That is why Paul could say to Titus, "Being justified by his grace we might become heirs according to the hope of eternal life." (Titus 3:7) And that is why Paul could say to the Romans, "[We] are justified by his grace as a gift, through the redemption that is in Christ Jesus." (Romans 3:24) We are justified, we are forgiven, we are granted grace, only through Jesus' atoning sacrifice. It was a gift. There was nothing we could do to gain justification; it was all on God's part. He chose us. He called us. And He justified us.
"And we know that for those who love God all things work together for good, for those who are called according to his purpose. For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers. And those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified." ~ Romans 8:28-30